Two Pivotal Vectibix Phase 3 Studies in First and Second-Line Treatment of Metastatic Colorectal Cancer Published in the Journal of Clinical Oncology

THOUSAND OAKS, Calif.,
Oct. 4 /PRNewswire-FirstCall/ --
Amgen (Nasdaq: AMGN) today announced that results from the PRIME
'203' and '181' pivotal Phase 3 trials evaluating Vectibix®
(panitumumab) in combination with chemotherapy (FOLFOX or FOLFIRI)
as a first and second-line treatment for metastatic colorectal
cancer (mCRC), respectively, were published online in the
Journal of Clinical Oncology.

"Both studies demonstrated that Vectibix administered
with chemotherapy significantly improved progression-free survival
in patients with wild-type KRAS mCRC," said Marc Peeters, M.D., Ph.D., Professor of
Oncology, Antwerp University Hospital and '181' trial lead
investigator and study author. "The adverse event profiles in both
trials were as expected for an anti-EGFR antibody treatment used in
combination with these types of chemotherapy regimens.
Additionally, these data reinforce that KRAS status should
be known when choosing treatment strategies."

These data confirm previous findings when oxaliplatin-based
chemotherapy and an anti-EGFR antibody were combined in patients
bearing tumors with activating KRAS mutations.

The response rate of Vectibix plus chemotherapy was higher than
chemotherapy alone in the wild-type KRAS patient population
as measured by blinded central review (55 percent versus 48 percent
in the FOLFOX only arm).

Tumor KRAS status was ascertained in 93 percent of the
1,183 patients enrolled in the PRIME '203' trial, the highest
number ever prospectively reported for a first-line trial.

"The outcome of this high quality trial demonstrated
that Vectibix, which was administered every two weeks, improved
progression-free survival as a first-line metastatic colorectal
cancer treatment in a selected patient population," said
Jean Yves-Douillard, M.D., Ph.D.,
director Clinical and Translational Research, Medical Oncology
Branch, Centre R Gauducheau, France and PRIME '203' trial lead investigator
and study author.

The addition of Vectibix to chemotherapy in the '181' trial
resulted in greater than a three-fold improvement (35 percent
versus 10 percent) in response rate in the wild-type KRAS
patient population, as measured by a blinded central review.

Tumor KRAS status was ascertained in 91 percent of the
1,186 patients enrolled in the '181' trial, the highest number ever
prospectively reported for a second-line trial.

In this study, the addition of Vectibix had no positive or
negative effect on PFS or OS in patients with tumors harboring
activating KRAS mutations.

"The response rate seen in the '181' trial is among the
highest ever reported in the second-line metastatic colorectal
cancer setting," said Emily Chan,
M.D., Ph.D., Assistant Professor of Medicine, Vanderbilt-Ingram
Cancer Center and '181' study investigator and author.
"Additionally, the tissue acquisition from both the '181' and '203'
studies has yielded a large repository of informative data
regarding the KRAS biomarker, and holds the potential of
providing even more information in the future."

In general, adverse events rates were comparable across
arms in both studies, with the exception of known toxicities
associated with anti-EGFR therapy, such as rash, diarrhea, and
hypomagnesemia. Vectibix-related grade 3/4 infusion reactions were
reported in less than one percent of patients.

Originally designed to compare the treatment effect in
the overall mCRC patient population, both studies were amended to
analyze outcomes with respect to the presence or absence of
activating mutations in KRAS in the tumor itself. These are
the first Phase 3 studies to prospectively analyze the effect of an
EGFR inhibitor based on KRAS status in patients with
previously treated mCRC.

Results from both trials were previously presented at
Europe's largest cancer
conference, ECCO 15 – ESMO 34, in September 2009, at the 2010 American Society of
Clinical Oncology (ASCO) Gastrointestinal Cancers Symposium in
January, and at the 2010 American Society of Clinical Oncology
(ASCO) Annual Meeting in June.

About the PRIME '203' Trial

Patients enrolled in the '203' or PRIME trial
(Panitumumab Randomized trial In combination
with chemotherapy for Metastatic colorectal cancer to
determine Efficacy) were randomized to receive either 6.0
mg/kg of Vectibix and FOLFOX4 once every two weeks (Q2W) or FOLFOX4
alone Q2W. The primary endpoint of the study was progression-free
survival by KRAS status and secondary endpoints included
overall survival, objective response rate, time to progression,
duration of response and safety. Long-term follow up for overall
survival is ongoing.

About the '181' Trial

The '181' trial is a global, multicenter, randomized
Phase 3 study. Patients enrolled in the study were randomized to
receive either 6.0 mg/kg of Vectibix and FOLFIRI Q2W or FOLFIRI
alone Q2W. The co-primary endpoints were progression-free survival
(which was independently tested) and overall survival. Secondary
endpoints included objective response rate, time to progression,
duration of response and safety by KRAS status.

AboutKRAS

Results from studies performed over the last 25 years
indicate that KRAS plays an important role in cell growth
regulation. In mCRC, EGFR transmits signals through a set of
intracellular proteins. Upon reaching the nucleus, these signals
instruct the cancer cell to reproduce and metastasize, leading to
cancer progression. Anti-EGFR antibody therapies work by inhibiting
the activation of EGFR, thereby inhibiting downstream events that
lead to malignant signaling. However, in patients whose tumors
harbor a mutated KRAS gene, the KRAS protein is
always turned "on," regardless of whether the EGFR has been
activated or therapeutically inhibited. KRAS mutations occur
in approximately 40 – 50 percent of mCRC patients.

About Colorectal Cancer

Colorectal cancer is the fourth most common cancer in
men and the third most common cancer in women worldwide.
Approximately 1.2 million cases of colorectal cancer are expected
to occur globally. With more than 630,000 deaths worldwide per
year, it is the third leading cause of cancer-related death in the
Western world. The highest incidence rates are found in
Japan, North America, parts of Europe, New
Zealand, and Australia, and
rates are low in Africa and
Southeast Asia. Rates are
substantially higher in men than in women.

About Vectibix

Vectibix is the first fully human anti-EGFR antibody
approved by the United States
(U.S.) Food and Drug Administration (FDA) for the treatment of
mCRC. Vectibix was approved in the U.S. in September 2006 as a monotherapy for the treatment
of patients with EGFR-expressing mCRC after disease progression on
or following fluoropyrimidine-, oxaliplatin-, and
irinotecan-containing chemotherapy regimens.

The effectiveness of Vectibix as a single agent for the
treatment of EGFR-expressing mCRC is based on progression-free
survival. Currently no data are available that demonstrate an
improvement in disease-related symptoms or increased survival with
Vectibix.

Retrospective subset analyses of mCRC trials have not
shown a treatment benefit for Vectibix in patients whose tumors had
KRAS mutations in codon 12 or 13. Use of Vectibix is not
recommended for the treatment of colorectal cancer with these
mutations.

In December 2007, the
European Medicine Agency (EMA) granted a conditional marketing
authorization for Vectibix as a monotherapy for the treatment of
patients with EGFR-expressing mCRC with non-mutated (wild-type)
KRAS after failure of fluoropyrimidine-, oxaliplatin-, and
irinotecan-containing chemotherapy regimens. Vectibix has been
launched in more than 20 European Union countries, Russia, Israel, Switzerland, Australia, Canada and Japan. Applications in the rest of the world
are pending.

The most common adverse events of Vectibix are skin
rash with variable presentations, hypomagnesemia, paronychia,
fatigue, abdominal pain, nausea, and diarrhea, including diarrhea
resulting in dehydration.

Important European Product Safety
Information

For full prescribing information please see the Summary
of Product Characteristics.

Vectibix is indicated as monotherapy for the treatment
of patients with EGFR-expressing, metastatic colorectal carcinoma
(mCRC) with nonmutated (wild-type) KRAS after failure of
fluoropyrimidine-, oxaliplatin-, and irinotecan-containing
chemotherapy regimens.

Vectibix is contraindicated in patients with a history
of severe or life-threatening hypersensitivity reactions to the
product and in patients with interstitial pneumonitis or pulmonary
fibrosis.

Other common adverse events of special importance
associated with Vectibix and/or EGFR monoclonal antibody therapies
include dermatologic-related reactions, pulmonary complications,
electrolyte disturbances and infusion-related reactions (including
rare reports with fatal outcome). These events should be monitored
carefully, see Summary of Product Characteristics for information
on appropriate management of these adverse events. Acute renal
failure has been observed in patients who develop severe diarrhoea
and dehydration.

Vectibix should not be used in combination with IFL
[bolus 5-fluorouracil (500 mg/m2), leucovorin (20 mg/m2) and
irinotecan (125 mg/m2)] or in combination with bevacizumab
containing chemotherapy.

Vectibix should not be administered in combination with
oxaliplatin-containing chemotherapy to mCRC patients with mutant
KRAS tumours or for whom KRAS tumour status is
unknown.

About Amgen

Amgen discovers, develops, manufactures and delivers
innovative human therapeutics. A biotechnology pioneer since 1980,
Amgen was one of the first companies to realize the new science's
promise by bringing safe and effective medicines from lab, to
manufacturing plant, to patient. Amgen therapeutics have changed
the practice of medicine, helping millions of people around the
world in the fight against cancer, kidney disease, rheumatoid
arthritis, and other serious illnesses. With a deep and broad
pipeline of potential new medicines, Amgen remains committed to
advancing science to dramatically improve people's lives. To learn
more about our pioneering science and our vital medicines, visit
http://www.amgen.com.

Forward-Looking Statements

This news release contains forward-looking statements
that are based on management's current expectations and beliefs and
are subject to a number of risks, uncertainties and assumptions
that could cause actual results to differ materially from those
described. All statements, other than statements of historical
fact, are statements that could be deemed forward-looking
statements, including estimates of revenues, operating margins,
capital expenditures, cash, other financial metrics, expected
legal, arbitration, political, regulatory or clinical results or
practices, customer and prescriber patterns or practices,
reimbursement activities and outcomes and other such estimates and
results. Forward-looking statements involve significant risks and
uncertainties, including those discussed below and more fully
described in the Securities and Exchange Commission (SEC) reports
filed by Amgen, including Amgen's most recent annual report on Form
10-K and most recent periodic reports on Form 10- Q and Form 8-K.
Please refer to Amgen's most recent Forms 10-K, 10-Q and 8-K for
additional information on the uncertainties and risk factors
related to our business. Unless otherwise noted, Amgen is providing
this information as of Oct. 4, 2010
and expressly disclaims any duty to update information contained in
this news release.

No forward-looking statement can be guaranteed and
actual results may differ materially from those we project.
Discovery or identification of new product candidates or
development of new indications for existing products cannot be
guaranteed and movement from concept to product is uncertain;
consequently, there can be no guarantee that any particular product
candidate or development of a new indication for an existing
product will be successful and become a commercial product.
Further, preclinical results do not guarantee safe and effective
performance of product candidates in humans. The complexity of the
human body cannot be perfectly, or sometimes, even adequately
modeled by computer or cell culture systems or animal models. The
length of time that it takes for us to complete clinical trials and
obtain regulatory approval for product marketing has in the past
varied and we expect similar variability in the future. We develop
product candidates internally and through licensing collaborations,
partnerships and joint ventures. Product candidates that are
derived from relationships may be subject to disputes between the
parties or may prove to be not as effective or as safe as we may
have believed at the time of entering into such relationship. Also,
we or others could identify safety, side effects or manufacturing
problems with our products after they are on the market. Our
business may be impacted by government investigations, litigation
and products liability claims. We depend on third parties for a
significant portion of our manufacturing capacity for the supply of
certain of our current and future products and limits on supply may
constrain sales of certain of our current products and product
candidate development.

In addition, sales of our products are affected by the
reimbursement policies imposed by third-party payors, including
governments, private insurance plans and managed care providers and
may be affected by regulatory, clinical and guideline developments
and domestic and international trends toward managed care and
healthcare cost containment as well as U.S. legislation affecting
pharmaceutical pricing and reimbursement. Government and others'
regulations and reimbursement policies may affect the development,
usage and pricing of our products. In addition, we compete with
other companies with respect to some of our marketed products as
well as for the discovery and development of new products. We
believe that some of our newer products, product candidates or new
indications for existing products, may face competition when and as
they are approved and marketed. Our products may compete against
products that have lower prices, established reimbursement,
superior performance, are easier to administer, or that are
otherwise competitive with our products. In addition, while we
routinely obtain patents for our products and technology, the
protection offered by our patents and patent applications may be
challenged, invalidated or circumvented by our competitors and
there can be no guarantee of our ability to obtain or maintain
patent protection for our products or product candidates. We cannot
guarantee that we will be able to produce commercially successful
products or maintain the commercial success of our existing
products. Our stock price may be affected by actual or perceived
market opportunity, competitive position, and success or failure of
our products or product candidates. Further, the discovery of
significant problems with a product similar to one of our products
that implicate an entire class of products could have a material
adverse effect on sales of the affected products and on our
business and results of operations.

The scientific information discussed in this news
release related to our product candidates is preliminary and
investigative. Such product candidates are not approved by the U.S.
Food and

Drug Administration (FDA), and no conclusions can or
should be drawn regarding the safety or effectiveness of the
product candidates. Only the FDA can determine whether the product
candidates are safe and effective for the use(s) being
investigated. Further, the scientific information discussed in this
news release relating to new indications for our products is
preliminary and investigative and is not part of the labeling
approved by the U.S. FDA for the products. The products are not
approved for the investigational use(s) discussed in this news
release, and no conclusions can or should be drawn regarding the
safety or effectiveness of the products for these uses. Only the
FDA can determine whether the products are safe and effective for
these uses. Healthcare professionals should refer to and rely upon
the FDA approved labeling for the products, and not the information
discussed in this news release.